Chapter 5 - Development And Plasticity Of The Brain

the production of new cells/neurons in the brain primarily occurring early in life

migration

movement of the newly formed neurons and glia to their eventual locations. migration occurs via cells following chemical paths in the brain of immunoglobins and chemokines

differentiation

forming of the axon and dendrite that gives the neuron its distinctive shape. the axon grows 1st either during migration or once it has reached its target and is followed by the development of dendrites

synaptogenesis

final stage of neural development and refers to the formation of the synapses between neurons

synaptic pruning

reducing the number of functional synapses. occurs throughout the life as neurons are constantly forming new connections and discarding old ones

neural darwinism

the idea of the selection process of neural connections. in this competition amongst synaptic connections, we initially form more connections than we need. the most successful axon connections and combinations survive while others fail to sustain active synapses

neurotrophin

chemical that promotes the survival and activity of neurons

apoptosis

developmental program by which a neuron kills itself at a certain age unless inhibited from doing so

nerve growth factor (NGF)

type of neurotrophin released by muscles that promotes the survival and growth of axons

brain-derived neurotrophic factor (BDNF)

helps support the survival and existing neurons, and encourage the growth and differentiation of new neurons and synapses

fetal alcohol syndrome

condition that children are born w/ if the mother drinks heavily during pregnancy. hyperactivity, impulsiveness, difficulty maintaining attention, varying degrees of mental retardation, motor problems and heart defects, facial abnormalities

focal hand dystonia ("musicians cramp")

condition where the reorganization of the brain goes too far. this condition is a result of extensive reorganization of the sensory thalamus and cortex so that touch responses to one finger overlap those of another

stem cells

undifferentiated cells found in the interior of the brain that generate "daughter cells" which can transform into glia or neurons

closed head injury

trauma that occurs when a sharp blow to the head drives the brain tissue against the inside wall of the skull

stroke

temporary loss of blood flow to the brain

ischemia

most common type of stroke, resulting from a blood clot or blocking of an artery. neurons lose their oxygen and glucose supply

hemorrhage

less frequent type of stroke resulting from a ruptured artery. neurons are flooded w/ excess blood, calcium, oxygen and other chemicals

Edema

the accumulation of fluid in the brain resulting in increased pressure on the brain

tissue plaminogen activator (tPA)

drug that breaks up blood clots and can reduce the effects of an ischemic strokes

penumbra

area of endangered cells surrounding an area of primary damage

diaschisis

decreased activity of surviving neurons after damage to other neurons

collateral sprouts

new branches formed by other non-damaged axons that attach to vacant receptors

denervation supersensitivity

the heightened sensitivity to a NT after the destruction of an incoming axon

disuse supersensitivity

the hypersensitivity to a NT after a result of inactivity by an incoming axon

phantom limb

continuation of sensation of an amputated body part and reflects this process